From the folding forum: 85% GPU Usage
Posted by tjlane of PG
I believe that this might be an unfortunate an common issue/feature of the p764x series going forward. The limitations are likely not software related, but hardware imposed. Specifically, these projects need to do a lot more file I/O than previous GPU projects, and the PCI bus that connects most GPUs to their motherboards are terribly slow. Since the calculations on the GPU are so fast, the PCI bus can't always keep up, and I suspect that this might be a limiting factor for these projects.
That said, the GPU performance still beats CPUs for these guys, so even though you're running at 85%, there is a significant speedup from the science end. So thanks for folding!
Having searched the web, I have come across a thread in the EVGA folding forums in which several other people are relating to the same issues i am having with this project. I must therefore conclude that the limiting factor is indeed PCI bus speed or latency. I have gone through all the release notes from previous NVidia drivers and rolled back to a previous driver to no avail. . . Bring on PCIe 3!
Another problem exists, all be it from a research point of view: The solution found on EVGA's forum for this problem is to remove the -advmethods flag from the GPU client, thus preventing project 764x from being downloaded. I believe many will take this option due to the drop in "points per day" from undertaking one of these projects over any other available work units and due to either not having the available overhead on their GPUs to overclock, or not having the stomach for it. The only options I can see, from Stanford's point of view would be either to distribute project 764x to those without the -advmethods flag specified in their client configuration (which would seem rather unfair), or to review the points awarded to completed simulations of project 764x in favour of their completion.
Seems to indeed be caused by a lack of bandwidth on PCI-E.
What you're cards running in Yan? My 570 is in x8 mode and gets 85-87% with those units.